An investigation has been launched into claims that British Metropolitan Police officers used a secret online forum to air racist views about ethnic groups.

A Metropolitan Police spokesman said "concerns" were raised about comments made on a Facebook group with the Directorate of Professional Standards (DPS) in April.

Representatives of the traveller community contacted police in June about the same Facebook group and these complaints were being "looked at in detail as part of the DPS assessment", according to the spokesman.

Some of the comments were made during a discussion in March about the BBC Trust's decision to clear Jeremy Clarkson and other Top Gear presenters of wrongdoing for their use of the word "pikey", a derogatory term for travellers, according to The Independent on Sunday.

The spokesman said: "The group administrators have set the privacy settings for the group as "secret" but we understand it to include former and serving MPS officers among its members.

"DPS is assessing the information it has received to determine whether any serving MPS officer or staff may have committed any acts of misconduct and will also look to see if any criminal offences may have been committed. Should either be disclosed they will be fully investigated."

Yvonne MacNamara, chief executive of the Traveller Movement, described the Facebook comments were "shocking", telling The Independent on Sunday: "The fact that they are potentially made by serving and retired police officers gives us no confidence at all in the Metropolitan Police's ability to both police these communities and to attract and protect its own staff who are from gypsy and traveller backgrounds."